Britain 'facing terrorist insider threat from foreigners working at airports'

Transport Secretary Ruth Kelly said that by the end of the year, applicants for sensitive 'airside' jobs would be vetted to see if they had committed offences abroad.

But those who already hold security passes - including pilots and baggage-handlers - will not be checked.

An armed policeman keeps watch at Heathrow. But checks on staff at airports must be beefed up, today's report warns

Critics said it exposes the 'worrying state of security' at airports.

Ministers are determined to close all possible loopholes to ensure terrorists cannot hijack or plant bombs on passenger jets.

Former civil servant Stephen Boys Smith warned of the possibility of 'terrorist insiders' at transport hubs in a recent report commissioned by Government ministers.

He said the threat of extremists infiltrating sensitive parts of airports is 'varied and unpredictable'.

Currently, restricted pass holders at airports face a standard UK criminal records check. But in May it was revealed that workers were not subject to overseas checks.

It meant hundreds of workers with a criminal past could have landed 'airside' jobs.

In a written statement, Miss Kelly said overseas criminal record checks are now a more viable option than they have been in the past.

She said mandatory checks for offences committed overseas should be carried out 'for those posts which present the highest risks, such as those with specific security responsibilities'.

But Miss Kelly warned that officials would have to overcome 'a number of legal and practical challenges' before the new rules could be introduced.

Liberal Democrat home affairs spokesman Chris Huhne said: 'It is a crazy hole in our airport security that we will do criminal record checks on British employees, but can't do the same for foreign ones.'